There were two kids I didn't get along with in elementary school. So during the winter, I took the hat of one of them and hid it in the other kid's locker (no locks were used back then). I anonymously reported the other kid by leaving a note on the teacher's desk. I went far as to disguise my handwriting. Anyway, the other kid got in trouble for "stealing the hat" and then both of them were too busy hating each other to mess with me anymore.

(SPOILER)